The present invention relates to a microparticulate pharmaceutical delivery system which is capable of ensuring that the pharmaceutical to be delivered can be directed to be absorbed in the Peyer's glands of the small intestine.
There are a number of enteric coatings which are utilized to ensure that acid labile pharmaceuticals or other materials can get safely by the acidic pH conditions in the stomach when ingested orally and which are dissolved in the alkaline pH conditions of the intestine and absorbed therein. However, there are many drugs in which it is desired to avoid exposure to both the acidic conditions of the stomach and the akaline conditions of the intestine and yet be absorbed in the intestine so they can be given in oral dosage form. Many pharmaceuticals are labile, inactivated or in some manner have their effectiveness limited in whole or in part, under the pH conditions existing in the stomach and intestine.
It is known that the small intestine comprises three main sections, the duodenum, jejunum, and the ileum. Located primarily in the ileum are Peyer's glands, often referred to as "Peyer's patches", which contain phagocytic cells which act to capture solid particles of ten microns or less that come into the intestine. This is important since particles cannot otherwise pass through the intestinal lining.
Some Peyer's glands exist in the jejunum particularly in the lower portion thereof as one comes to the ileum, but they are few in number and most are located in the ileum. Occasionally, and rarely, some are seen in the duodenum.
Heretofore, a satisfactory procedure to give oral doses of pharmaceuticals for delivery to the Peyer's patch that are acid and akali labile has not been available.